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Ammonia
Ammonia poisoning is one of the biggest killers of aquarium fish. It occurs most often when a tank is newly set up. However, it can also occur in an established tank when too many new fish have been added at one time, when the filter fails due to power or mechanical failure, or if bacterial colonies die off due to the use of medications.
Some of the telltale signs that fish are suffering ammonia poisoning include:
Fish gasp for breath at the surface.
Purple or red gills.
Fish is lethargic.
Loss of appetite.
Fish lay on the bottom of the tank.
Red streaking on the fins.
Ammonia poisoning can happen suddenly, or over a period of days. Initially the fish may be seen gasping at the surface for air. The gills will begin to turn red or lilac in colour, and may appear to be bleeding. The fish will begin to lose their appetite and become lethargic. In some cases fish may be seen lying on the bottom of the tank with clamped fins.
As the damage from the ammonia continues, the tissues will be damaged as evidenced by red streaks or bloody patches that appear on the body and fins. Internal damage is occurring to the brain, organs, and central nervous system. The fish begins to haemorrhage internally and externally, and eventually dies.
If your fish show any symptoms of ammonia poisoning you should immediately test the aquarium water, if the water tests with any ammonia you should:
Lower the pH below 7.0.
Do a 30 - 50% water change.
Use chemicals to neutralize ammonia.
Reduce feeding.
Lowering the pH of the water will provide immediate relief, as will a 50% water change (be sure to use water that is the same temperature as the aquarium). Several water changes within a short period may be required to drop the ammonia to below 1ppm.
If the fish are in severe distress, the use of chemicals to neutralize the ammonia is recommended. Feedings should be reduced so that waste is reduced. In cases of high ammonia levels, feedings should be discontinued for several days. No new fish should be added until the ammonia levels have fallen to zero.
Because ammonia toxicity is linked to the pH, testing of both ammonia and pH levels are critical. Ammonia becomes increasingly toxic as the pH rises above 7.0.
At a level of 1ppm or 1 mg/l, fish are under stress. Levels even lower than that can be fatal if the fish are exposed continuously for several days. For that reason it is critical to continue daily testing and treatment until the ammonia drops to zero. When ammonia levels are elevated for a long period, it is not unusual to lose fish even after the ammonia levels have drop to zero.
The key to avoiding fish death from ammonia poisoning is to avoid ammonia spikes in the first place. When starting a new tank, add only a few fish initially and do not add more until the tank is completely cycled. Even in a well-established tank, only add a few fish at a time and avoid overcrowding.
Feed fish small quantities of foods, and remove any uneaten food. Clean the tank weekly, taking care to remove any dead plants or other debris. Perform a partial water change at least every 2 weeks, more often in small heavily stocked tanks. Test the water for ammonia regularly to detect problems before they become serious.
Nitrite
Nitrite follows closely to ammonia as a major killer of fish. Anytime ammonia levels are elevated, elevated nitrites will soon follow. To avoid nitrite poisoning, test levels when setting up a new tank or when adding new fish to an established tank, when the filter fails due to power or mechanical failure, and when using medications.
Also known as 'brown blood disease' because the blood turns brown from a increase of methemoglobin. However, methemoglobin causes a more serious problem than changing the colour of the blood. It renders the blood unable to carry oxygen, and the fish can literally suffocate even though there is ample oxygen present in the water.
Different species of fish tolerate differing levels of nitrite. Some fish may simply be listless, while others may die suddenly with no obvious signs of illness. Common symptoms include gasping at the surface, hanging near filter outlets, rapid gill movement, and a change in gill colour from tan to dark brown.
Fish that are exposed to even low levels of nitrite for long periods of time suffer damage to their immune system and are prone to secondary diseases, such as ich, fin rot, and bacterial infections. As methemoglobin levels increase damage occurs to the liver, gills and blood cells. If untreated, affected fish eventually die from lack of oxygen, and/or secondary diseases.
The addition of one gram of aquarium salt per 2 litre of water will prevent methemoglobin from building up. Aeration should be increased. Feedings should be reduced and no new fish should be added until nitrite levels are reduced to zero.
If your fish show any symptoms of nitrite poisoning you should immediately test the aquarium water, if the water tests with nitrite you should:
Do large water change.
Add aquarium salt.
Reduce feeding.
Increase aeration.
Nitrite is lethal at lower levels than ammonia. Therefore continue daily testing and treatment until the nitrite falls to zero.
Nitrate
Although less toxic than ammonia and nitrite, excess nitrate causes stress making a fish’s organs work harder to adjust to their environment. The increasing stress results in the fish losing the ability to fight diseases, heal themselves and reproduce.
It is essential for you, to maintain a proper environment for your fish. High nitrate levels are a sign of poorly maintained aquariums and will cause problems.
Nitrate is the result of the nitrification process therefore it will always be present, plants utilize nitrate so having may plants in an aquarium will help control nitrate levels but even plants suffer if nitrate levels are to high (30ppm). This is due to an accumulation of live forms feeding from the waste, and the consequently higher biomass (animals living in the aquarium) leads to an increasing demand of oxygen. There is only one sure way of controlling nitrate levels and that is to do regular partial water changes, now there are may people who will tell you to change 20%, 30%, 40%, or even 50% weekly, fortnightly or monthly, there is no hard and fast rule to the amount and how often you need to change water there are just to many variables but there is an average, if you have a moderately stocked tank with a good number of plants and good filtration a 25%-30% fortnightly will usually be adequate. The correct way to determine the water change needs of you tank is to test the water Ph and nitrate levels before and after water changes, if the Ph is lower and the nitrate is higher after a water change than the result after the previous water change that the frequency or amount need to be increased.
Another sign that nitrate levels are high is the appearance of excessive algae, algae thrives in water where nitrate levels are above 10ppm so keeping nitrate levels low will also help reduce the outbreak of algae.
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